[evlatests] Delay change for antenna 9

[Rick Perley]

    I wrote earlier that antenna 9 changed delay by 4 nsec in the middle 
of the 4-band tracking test (Tuesday night). 

    I've now reviewed all the data.  The delay changed *in the middle of 
a scan* -- between 14:17:21.5 and 14:17:25, when we were observing the 
source at L-band.  Between these times, the delay was in no steady 
state.  After the latter time, it was at a new value, 4 nsec away from 
earlier.  All bands were affected equally. 

    How can this happen?